Shielded jack



Jan. 17,1967 J .J D'IXON 3,298,664-

'SHIELDED JACK Filed Aug. 27, 1964 s Sheets-$heet 2 Jan. 17, 1967 J. J.DIXON 3,298,664

' SHIELDED JACK Filed Aug 27, 1964 3 Sheets-Sheet :5

54 zOM Jrz/c/ m v 4; 1 40M haw a I 4 wrceys United States PatentO3,298,664 SHIELDED JACK John J. Dixon, Charlotte, N.C., assignor toDuff-Norton Company, Charlotte, N.C., a corporation of North CarolinaFiled Aug. 27, 1964, Ser. No. 392,547 12 Claims. (Cl. 254-93) Thepresent invention relatesto a shielded jack, and more particularly thattype of jack or ram which receives pressure fluid operating againstapiston within a cylinder, and is capable of capacitiesranging up to 100tons in general commercial application, and 500 tons for specialapplications. I

Jacks and rams designed for loads up to 100 tons are used in a widevariety of applications ranging from house moving to employment inshipyards, and in railroad yards. Necessarily, the extensible portionsof any rams or' jacks employed in such usages are subjected to theravages of weather, salt spray, sand, scale, grit, and corrosion whichcause pitting of the rams and eventual scoring to the point wherethejack or ram is rendered inoperable. Furthermore, the costs of renderingsuch jacks or rams double-acting either by hydraulic means, or springreturn means, .is substantial as opposed to a single acting unit. Thedouble acting springs add substantially to the weight of such units aswell. handled by such large capacityrams or jacks for the applicationsreferred to above and other applications are seldom ideally positionedupon'the center of the longitudinal axis of the ram plunger or cylinder.The side loads are such as to cause bindingat' the support glands, andoften on the piston where it bears against the inner wall of the ramcylinder.

With the foregoing difficulties and shortcomings of the commerciallyavailable jacks or rams in mind, it is the general object of the presentinvention to provide a shielded jack or ram which substantially reduceswear attributable to corrosion and contamination. An additional andimportant related object of the invention is to provide a shielded ramwhich is double-acting under no-load conditions in order to lower thetop plate back to the fully lowered position without the employment ofadditional hydraulic valving, or return springs.

Another closely related and important object of the invention, andadvantage achieved thereby, is the em- In addition, the loads which areployment of a swivel head on the top of the ram plunger or piston toaccommodate loads which are not'perfectly oriented for perfectlyhorizontal or perpendicular relationship with the ram plunger and ramcylinder.

Additional objects of the invention include providing a shielded jack orram construction with reduces scoring, holds corrosion to a minimum, andis inexpensive t manufacture.

Still another object of the invention looks to the construction of ashielded jack or ram which renders the same inherently susceptible ofmanufacture out of aluminum, and other light-weight materials to therebysubstantially reduce the weight for a given capacity.

Another object of the invention looks to the provision of a shieldedjack or ram in which the expendible parts can be readily replaced in thefield in the event of their the jack or ram shownin FIG. 1 illustratingsequentially Patented Jan. 17, 1967 illustrating in detail with slightexaggeration the upper portion of the ram or jack as shown in FIG. 4.

FIGURE 6 is an enlarged transverse sectional partially broken view,taken along section line 4-4 of FIG. 3 illustrating the lower portion ofthe ramor jack in its details.

FIGURE 7 is an enlarged view of the upper portion of the ram or jacktaken along section line 4-4 of FIG. 3 and similar to the top portion ofFIG. 5 but in which the swivel top plate has been shown in exaggeratedform in a cocked or angled position.

FIGURE 8 is a front elevation of a modified configuration of the subjectshielded jack, showing the jack or ram in its extended position inphantom lines.

FIGURE 9 is atop elevation of the jack shown in FIG. 8 in the same scaleas shown in FIG. 8.

FIGURE 10 is an enlarged scale transverse sectional view o'f the jackshown in FIGS. 8 and 9 taken along section line 10-10 of FIG. 9.

FIGURE .11 is an enlarged partially broken transverse sectional view ofthe upper portion of the modified jack shown in FIGS. 8 through 10,showing an alternative embodiment of the top plate.

In broad outline the structure of the illustrative embodiment of theinvention, as best illustrated in FIGS. 1 and 4, contemplates agenerally cylindrical ram 10 with the exterior primarily encased by atubular sleeve 20, here shown as cylindrical in configuration. A handle12 is provided for hand-carrying by operators to any position whereinthe ram 10 is to be used, whereupon the cylinder 14, and moreparticularly its flattened base portion, is positioned upon a solidlocation. The fluid lead 16 supplies pressure fluid which actuates theplunger 3-0 and directs it upwardly against the swivel top plate 18. Theelastomeric sleeve20 is secured to the cylinder by means of. the sleeveclamp 22, and secured to the top plate 18 by means of the sleeve neck24. Thus as the swivel top plate engages the load, and moves upwardly,the sleeve 20 extends with it and effectively shields the extendedportion of the piston 30 from contact with the corrosive atmosphere,grit, and the like. After the end of the lifting stroke is achieved (seeFIG. 2) and when the hydraulic pressure. is reduced and the fluid ispermitted to flow from the cylinder, sufficient potential energy isstored in the extended walls of the sleeve 20 to return the plunger 30to its retracted position by means of the sleeve neck 24 and itsassociated neck reinforcing ring 26 bearing on the sleeve neck shoulder28 which is a peripheral portion of the swivel top plate 18. The curvedinterface between the swivel top plate 18 and the plunger 30 permits theupper flat face of the swivel top plate to tilt (see FIG. 7) in such amanner as to accommodate loads which are applied at a position otherthan perfectly aligned with the longitudinal axis of the plunger 30.

Thus the unique inter-action between the sleeve 20 and the top plate 18achieves a threefold purpose of shielding the jack 10 from exteriorcorrosive and contaminating ele ments; providing a no-load double-actingeffect to return the plunger 30 to its retracted position, and yieldablyand shiftably securing the swivel top plate 18 in engagement with theupper portion of the piston 30. Additional advantages'and purposes ofthe invention will become further apparent as this description of theillustrative jack proceeds, and takes into account the minimal number ofparts employed for construction. In addition, as will be pointed outhereinafter, this construction admits of manufacture by means of a ramcylinder made of an aluminum alloy which greatly reduces the weight ofthe overall unit. The inherent characteristics which eliminatecorrosion, contamination, and pitting tendencies from the plunger assistin making such a lightweight construction possible. Furthermore, thisconstruction can be achieved within manufacturing tolerances which areinherently economical.

The driving force from the pressure fluid which is led into the cylinder14 by means of the fluid lead 16 is achieved primarily through theprovision of a bronze follower plate 32 at the lower portion of theplunger 30. The outside diameter of the follower plate 32 approximatesthat of the cylinder wall 40, but leakage of the pressure fluid whichbears beneath the follower plate 32 A is prevented by means of the cupwasher packing 34. The cup washer has an exterior depending flangeportion which is self energized into pressurewiping contact with theinterior cylinder wall 40. A cup washer retainer 36 is provided tosecure the cup washer firmly against the operating head portion of thefollower plate 32, and is removably secured in place by the threadedretainer stud portion 38 which threadedly engages the interior of theplunger 30. A separator portion 37 is provided to insure againstcrushing the annular portion of the cup washer packing 34.

A gland nut 42, preferably manufactured of bronze, is provided in theconfiguration of a collar having an exterior threaded portion whichengages the interior upper threaded portion of the cylinder 14 at athreaded gland connection 44. The bearing surface of the glandapproximates one-half of'the diameter of the plunger, but may vary to alarger or lesser percentage of that diameter. It

will be also noted that the thickness of the follower plate 32 isapproximately 20% of the diameter of the follower plate 32. In thismanner the length of travel available within a given cylindrical housing14 is maximized, and yet the ability to carry side thrust is retained.

As will be observed in FIGS. 4 and 5, a sleeve breathing chamber 47 isdefined between the interior portion of the sleeve 20 and the exteriorwall of the cylinder 14. Open communication is provided between thebreathing chamber and atmosphere by means of the breathing port 48positioned at the upper portion of the cylinder 14' irrificienttolerance so that, in effect, the top plate 18 can rock I.

on the top of the plunger 30, the same being yieldably urged into alevel configuration by the restraining action of the elastomericcylinder sleeve 20. An annular limiting shoulder 57 is provided beneaththe top plate 18 and adjacent the concave seat 56 to limit tilting to 5.

It will be observed that the sleeve neck 24 and its associated neckreinforcing ring 26 bear down on the peripheral sleeve neck shoulder 28on the top plate 18. Since the pull of the side walls of the sleeve 20is relatively even, the tendency in the unloaded position will be for Ithe swivel top plate 18 to assume a relatively level position of reposeas illustrated in FIG. 5. No other structural members, or complicatedfittings are required to secure the swivel top plate 18 to the plunger30 apart from the constricted top of the elastomeric sleeve 20. It

is contemplated, however, that other techniques for attaching the upperportion of the tubular sleeve 20 to'the -a black neoprenetype rubber.

swivel top plate 18 may be employed, such as a snap ring into a recessedchanneled ring in the swivel top plate 18, or even positive securernentto a top plate 18 which does not swivel but rather is in fixed intimatecontact with the plunger 38 where the swiveling action is not requiredin the particular jack construction.

The lower portion of the elastomeric sleeve 28 is secured to the wallsof the cylinder 14 by means of a clamping band, here shown as a typicalWittek stainless clarnp band 58 which is threadedly and firmlyconstricted by means of the clamp screw 60 (see FIG. 2). The lower endof the elastomeric sleeve 20 is shown with a sleevemounting shoulderportion 62 in FIG. 6, in a peripheral ring or groove 63 provided aroundthe ex terior of the cylinder 14 to matingly and lockingly receive thelower end of the sleeve 20 by means of a physical interlock with thesleeve mounting shoulder portion 62. Various alternative attachmentmeans such as tongue and groove, plural studs, ribbed rubber face, andthe like, are contemplated for the lower end of the elastomeric sleeve20, as indicated with regard to the employment of the neck portion 24engaging the top swivel plate 18 discussed above. In the constructiondisclosed and described in detail regarding FIGS. 5 and 6,. it will beappreciated that the elastomeric sleeve 20' may be replaced by merelyunscrewing the clamp screw 68, physically removing thesleeve from theouter portion of the cylinder 14, and dropping another sleeve in place,and tightening the clamp screw 60. 'No tools other than a pair of pliersor a screwdriver need be employed for this replacement of the principalelement which is subjected to damage from the type of rough handlingthat jacks and rams of this character are normally subjected to inusage. A similar case of replacement of the remaining parts of the jackor ram 10- is made by removing the gland nut 42, and removing theplunger 30 from its chamber. Thereafter the cup washer retainer 36 maybe readily removed to replace the cup washer packing 34, and if need "beat this time, a new gland nut 42 placed in the jackor ram 10. In thismanner virtually every moving part, every part susceptible ofaccelerated wear, and every part'which is critical from a standpoint ofsmooth operation can be replaced with simple tools in the field; andmore importantly a ready supply of a few spare parts will insurecontinuous operation in the field.

While various elastomeric materials such as neoprene, synthetic rubbersof all types, extended synthetic rubber, .and urethane type rubbers arecontemplated for the sleeve 20, good commercial success has beenexperienced with Equivalent constructions such as spring loaded bellowsmay be substituted for the elastomeric sleeve 20, but are more expensiveand must be justified by the particular economics of the application.

The cup washer 34 which serves as a packing beneath the follower plate32 may be ideally also fabricated from a urethane composition; however,leather packing and other similar substitutes known in the art arecontemplated. As pointed out above, the gland nut 42 is preferablymachined from bronze to accept the wear of the plunger 30, which ispreferably chrome plated for hard ness and corrosion resistance. Thefollower plate 32 is fabricated from bronze the same as the gland nut42. The inner wall of the cylinder, which is fabricated and machinedfrom a suitable aluminum alloy is preferably .coated with HoughtonCindol, thereby providing a very bodiment described in detail above, arecommon, are

designatedby the suffix M. Where the parts differ,

they are separately identified. As will be noted in FIG. 8, where thealternative ram M is shown in its retracted position, it gives theappearance of being a shorty version. In such units the length of travelis relatively shorter than that of the similar capacity unitsproportioned as the first embodiment. The elastomeric sleeve M issecured by means of a sleeve clamp assembly 22M through the clampingband 58M secured by the clamping screw 60M. As observed in FIG. 10, theswivel top plate 18M has a concaved undersurface meeting at a curvedinterface 50M with the upper portion .of the piston 30M; The gland nut42M has a threaded interface 44M with the cylinder-14M, and is providedat its interior face with an annular limiting shoulder 57 as in the.first embodiment.

Differences in structure, however, are employed in the lower or baseassembly. As will be seen particularly in FIG. 10, the follower plate32M has on its upper face a shoulder 66 with an isosceles trapezoidalconfiguration, the same serving to'lockingly' engage the cup washerpacking 34M. The follower plate mounting stud 68 extends from the bottomof the piston 30M, and is pro- .vided with an. annular ring in which theseal 72 is seated above the threaded interface 70. A breathing vent 74is provided adjacent the locking ring 63M of the clastomeric sleeve 20M,adjacent the sleeve mounting shoulder portion 62M. The breathing vent 74may be formed as a key-way and provides an opening into the sleevebreathing chamber 47M, and connects the same with atmosphere.

A second alternative construction, differing from the other embodimentsprimarily as to the relationship between the swivel top plate 18 and theupper portion of the piston 30M, is disclosed in FIG. 11. There it willbe seen that the swivel top plate 18 has a central bore 76, and amounting stud 78 at its base extending through a mounting port 80 at thetop of the convex face 82 of the swivel top plate 18. The lockingshoulder 84 of the mounting stud 78 engages the annular wall of thecentral bore 76 of the top plate 18 when the limit of swivel travel isreached. The elastomeric sleeve 20M is secured to the top plate 18 in amanner similar to the other embodiments, and the base portion may beeither of the two base portions of the two previously describedembodiments. The third alternative embodiment shown in FIG. 11illustrates how the convex-concave relationship between the swivel topplate 18 and the piston 30 may be reversed, and how a different annularshoulder may be employed to limit the swivel or travel of the top plate18. The venting in the construction shown in FIG. 11 may be the same asthe first embodiment, or the second embodiment, or in addition ventingcan be achieved by perforations in the sidewall of the elastomericsleeve 20, or through a tube (not shown) into a diaphragm chamber sothat complete sealing can be achieved, and submerged operation thenbecomes possible for this particular ram or jack.

While the various embodiments of the jacks 10 shown here have beendisclosed as actuated by a hydraulic fluid, it will 'be appreciated thatwith differing drive means, such as pneumatic, mechanical, or evenelectrical solenoid types, a sleeve construtcion of the characterdisclosed in combination with a cylinder and plunger will have distinctadvantages in operation. The various types of power are contemplated,and there is no intention to limit the invention to the specificembodiments shown. Similarly various materials have been disclosed, andfinishing and fabricating techniques referred to as commerciallyadvantageous, but there is no intention to limit the invention to suchdetails of manufacture.

In review it will be seen that a ram or jack has been illustrated anddescribed having a construction which gives an inexpensive, lightweight,durable, and multifeatured product. The provision of the unique sleeveconstruction provides for double action in no-load condition, shieldsthe extended plunger from corrosion and contamination, and additionallyprovides a mount for the adjustable load engaging members.

While the invention has been described in connection with specificembodiments and applications, no intention to restrictthe invention tothe examples shown is contemplated, but to include within the inventionall of that subject matter defined by the spirit as well as the letterof the annexed claims.

I claim:

1. A no-load return shielded jack comprising a plunger, a housing forthe plunger, said housing having a support base, power means foractivating the plunger in one direction, a load support top plateengaging the plunger outer end, and an elastomeric sleeve exteriorlysecured to the housing and at one end to the top plate, said sleevehaving suflicient potential energy storage capacity to retract theplunger when deactivated, whereby the sleeve shields the plunger uponextension from the housing, and upon deactivation of the power theelasticity of the sleeve returns the plunger to its retracted position.

2.. A shielded jack comprising a plunger, a cylindrical housing for theplunger, said housing having a support base, fluid power means foractivating the plunger in one direction, a load support top lateengaging the plunger outer end, and an elastomeric sleeve securedexteriorly at one portion tothe housing and secured at one end to thetop plate, said sleeve having sufficient potential energystoragecapacity to retract the plunger when deactivated, whereby the sleeveshields the plunger upon extension, the, elasticity of the sleevereturning the plunger to its retracted position after extension.

3. A shielded jack comprising a plunger having an outer end and pistonportion, a cylindrical housing for the plunger from which the outer endof said plunger extends, fluid power means for activating the plunger inone direction by bearing on the piston portion of said plunger, a loadsup-port top plate shiftably engaging the plunger outer end, and atubular elastomeric sleeve secured circumferentially at one portion ofthe housing and secured at one end to the load support plate; wherebythe sleeve shields the plunger upon extension from the cylinder, theelasticity of the sleeve returning the plunger to its retracted positionafter extension, and the attachment of the sleeve to the top plateserves to yieldably swivel the top plate.

4. A shielded jack comprising, in combination, an elastomeric exteriorsleeve, means defining a neck at one end of said sleeve, a rigid bodydefining a central chamber and having an exterior portion adapted forengagement with said sleeve, said rigid body having a support base,attachment means adapted to circumferentially secure the sleeve to therigid body at a spaced position from the sleeve neck, plunger meansactuated by an applied force within said central chamber and having anupper portion extensible out of said chamber a load support top plateengaging the plunger outer end, and sleeve attachment means on said topplate adapted to engage the sleeve neck whereby the sleeve shields theextensible portion of the plunger, said sleeve having suflicientpotential energy storage capacity to retract the plunger whendeactivated.

5. A shielded jack comprising, in combination, an elastomeric tubularsleeve, means defining a neck at one end of said sleeve, a rigid bodydefining a central chamber and having an exterior portion incircumferential engagement with said sleeve, said rigid body having asupport base, plunger means actuated by an applied fluid force withinsaid central chamber and having an upper portion extensible out of saidchamber, a load support top plate engaging the plunger outer end, andsleeve attachment means on said top plate adapted to engage the sleeveneck where by the sleeve shields the extensible portion of the plunger,said sleeve having sufficient potential energy storage capacity toretract the plunger when deactivated.

6. A shielded jack comprising, in combination, an elastomeric tubularsleeve, means defining a neck at one end of said tubular sleeve, acylindrical rigid body defining a central chamber and having an exteriorportion adapted for engagement with said tubular sleeve, said housinghaving a support base, clamping means for releaseably securing thetubular sleeve to the cylindrical rigid body spaced from the neckportion of the sleeve, plunger means actuated by an applied pressurefluid force within said central chamber and having an upper portionextensible out of said chamber, a load support top plate engaging theplunger outer end, and sleeve attachment means on said top plate adaptedto engage the sleeve neck whereby the sleeve shields the extensibleportion of the plunger, said sleeve having sufiicient potential energystorage capacity to retract the plunger when deactivated.

7. A shielded jack comprising, in combination, a cylinder having aninterior cylinder chamber, a plunger journaled in said chamber forlongitudinal movement, a convex end on said plunger, a swivel top platewith a concave base proportioned to matingly engage the plunger convexend, shoulder means on the periphery of the swivel top plate, powermeans for moving the plunger Within the cylinder, an elastomeric sleeveproportioned to surround the cylinder, attachment means for securingsaid sleeve to the cylinder, and a constricted neck at the upper end ofthe elastomeric sleeve proportioned to engage the swivel top plateshoulder means so that extension of the plunger and its associated topplate extends the elastomeric sleeve, the extension resulting in areturn potential to retract the plunger after the power source directedto the plunger is withdrawn, the extended portion of the plunger beingshielded by the sleeve during the motion of the plunger.

8. A shielded jack comprising, in combination, a cylinder having aninterior cylindrical chamber, a plunger longitudinally and rotatablyjournaled in said chamber, a curved end on said plunger extending fromsaid chamber, a swivel top plate with a curved base proportioned tomatingly engage the plunger curved end, power means for moving theplunger within the cylinder, an elastomeric imperforate sleeveproportioned to surround the cylinder, attachment means for securing thesleeve to the cylinder, a constricted neck at the upper end of theelastomeric sleeve proportioned to engage the swivel top plate so thatextension of the plunger and its associated top plate extends theelastomeric sleeve, the extension resulting in a return potential toretract the plunger after the power source directed on the plunger iswithdrawn, the extended portion of the plunger being shielded by thesleeve during the motion of the plunger.

9. -A shielded jack comprising, in combination, a cylinder having aninterior cylindrical chamber, a plunger journaled in said chamber, aconvex end on said plunger, a piston portion .on the other end of saidplunger and within said chamber, a swivel top plate with a concave baseproportioned to matingly engage said plunger convex end, shoulder meanson the periphery of the top plate, power means for moving said plungerwithin said cylinder, an elastomeric sleeve proportioned to surround thecylinder, attachment means for removably securing said sleeve to thecylinder, and a constricted neck at the upper end of the elastomericsleeve proportioned to engage the swivel top plate shoulder means.

10. A shielded jack comprising, in combination, .a cylinder having aninterior cylindrical chamber, a plunger journaled in said cylinder, apiston head removably secured to said plunger, removable and replaceablesealing means held between the piston and plunger proportioned tocircumferentially engage the cylindrical chamber Wall, a curved end onsaid plunger, a swivel top plate with a curved base proportioned tomatingly engage the plunger curved end, shoulder means on the peripheryof the top plate, fluid power means for moving the plunger within thecylinder, an imperforate elastomeric sleeve proportioned to surround thecylinder, circumferential .clamping means removably securing the sleeveto the cylinder, and a constricted neck at the upper end of theelastomeric sleeve proportioned to engage the swivel top plate shouldermeans so that extension of the plunger and its associated top plateextends the elastomeric sleeve, the extended portion of the plungerbeing shielded by the sleeve.

11. In the shielded jack of claim 10, a removable gland securedto theupper end of the cylinder journaling the plungerat the swivel plate end,the pistonjournaling the same at the other end, thereby permittingreplacement and disassembly through the sequential release of the sleeveclamp and removal of the gland.

12. In the shielded jack of claim 10, annular shoulder means in theswivel top plate to limit cocking action to 5 References Cited by theExaminer.

UNITED STATES PATENTS 884,694 4/1908 Weant 92-132 1,745,067 1/ 1930Torrance. 2,416,796 4/ 1947 Dobbs. 2,571,615 10/1951 Romeo. 3,202,231 8/1965 Butterworth 254-86 X WILLIAM FELDMAN, Primary Examiner.

OTHELL M. SIMPSON, Examiner.

1. A NO-LOAD RETURN SHIELDED JACK COMPRISING A PLUNGER, A HOUSING FORTHE PLUNGER, SAID HOUSING HAVING A SUPPORT BASE, POWER MEANS FORACTIVATING THE PLUNGER IN ONE DIRECTION, A LOAD SUPPORT TOP PLATEENGAGING THE PLUNGER OUTER END, AND AN ELASTOMERIC SLEEVE EXTERIORLYSECURED TO THE HOUSING AND AT ONE END TO THE TOP PLATE, SAID SLEEVEHAVING SUFFICIENT POTENTIAL ENERGY STORAGE CAPACITY TO RETRACT THEPLUNGER WHEN DEACTIVATED, WHEREBY THE SLEEVE SHIELDS THE PLUNGER UPONEXTENSION FROM THE HOUSING, AND UPON DEACTIVATION OF THE POWER THEELASTICITY OF THE SLEEVE RETURNS THE PLUNGER TO ITS RETRACTED POSITION.